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1.
Felipe Samuel Pessoto Natalia Mayumi Inada Maria de Fátima Nepomuceno Ana Célia Ruggiero Anibal E. Vercesi 《Chemico-biological interactions》2009,181(3):400-408
In this paper, we present a study about the influence of the porphyrin metal center and meso ligands on the biological effects of meso-tetrakis porphyrins. Different from the cationic meso-tetrakis 4-N-methyl pyridinium (Mn(III)TMPyP), the anionic Mn(III) meso-tetrakis (para-sulfonatophenyl) porphyrin (Mn(III)TPPS4) exhibited no protector effect against Fe(citrate)-induced lipid oxidation. Mn(III)TPPS4 did not protect mitochondria against endogenous hydrogen peroxide and only delayed the swelling caused by tert-BuOOH and Ca2+. Fe(III)TPPS4 exacerbated the effect of the tert-BuOOH, and both porphyrins did not significantly affect Fe(II)citrate-induced swelling. Consistently, Fe(III)TPPS4 predominantly promotes the homolytic cleavage of peroxides and exhibits catalytic efficiency ten-fold higher than Mn(III)TPPS4. For Mn(III)TPPS4, the microenvironment of rat liver mitochondria favors the heterolytic cleavage of peroxides and increases the catalytic efficiency of the manganese porphyrin due to the availability of axial ligands for the metal center and reducing agents such as glutathione (GSH) and proteins necessary for Compound II (oxomanganese IV) recycling to the initial Mn(III) form. The use of thiol reducing agents for the recycling of Mn(III)TPPS4 leads to GSH depletion and protein oxidation and consequent damages in the organelle. 相似文献
2.
The kinetics of the reactions of three trans-dioxoruthenium(VI) porphyrin derivatives with organic sulfides were measured. The dioxo systems studied were 5,10,15,20-tetramesityl porphyrin-dioxoruthenium(VI) (2a), 5,10,15,20-tetraphenylporphyrin-dioxoruthenium(VI) (2b), and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin-dioxoruthenium(VI) (2c). Species 2 were competent oxidants and reacted rapidly with thioanisoles to generate the corresponding sulfoxides. Typical second-order rate constants determined from pseudo-first-order kinetic studies for sulfoxidation reactions are 8-60 M− 1 s− 1, which are 3 orders of magnitude larger in comparison with those of well studied alkene epoxidations and activated C-H bond oxidations by the same dioxo species. For a given sulfide substrate, the reactivity order for the dioxoruthenium(VI) species was 2a < 2b < 2c, which is in agreement with expectation on the basis of the electron-withdrawing and steric effects of the porphyrin macrocycles. Various para-substituted thioanisoles react in a narrow kinetic range with the same dioxo species. The kinetic results obtained in this study indicate a concerted oxygen atom transfer and/or electron transfer followed by oxygen transfer mechanism from oxidant to sulfide. Competition kinetic reactions with a catalytic amount of porphyrin ruthenium(II) species and a terminal oxidant give relative rate constants for sulfoxidations of competing substrates that are somewhat smaller than the ratios of absolute rate constants, implying a multiple oxidant model for sulfoxidation reactions. 相似文献
3.
4.
DeFreitas-Silva G Rebouças JS Spasojević I Benov L Idemori YM Batinić-Haberle I 《Archives of biochemistry and biophysics》2008,477(1):105-112
Mn porphyrins are among the most efficient SOD mimics with potency approaching that of SOD enzymes. The most potent ones, Mn(III) N-alkylpyridylporphyrins bear positive charges in a close proximity to the metal site, affording thermodynamic and kinetic facilitation for the reaction with negatively charged superoxide. The addition of electron-withdrawing bromines onto beta-pyrrolic positions dramatically improves thermodynamic facilitation for the O2*- dismutation. We have previously characterized the para isomer, Mn(II)Br(8)TM-4-PyP(4+) [Mn(II) beta-octabromo-meso-tetrakis(N-methylpyridinium-4-yl)porphyrin]. Herein we fully characterized its meta analogue, Mn(II)Br(8)TM-3-PyP(4+) with respect to UV/vis spectroscopy, electron spray mass spectrometry, electrochemistry, O2*- dismutation, metal-ligand stability, and the ability to protect SOD-deficient Escherichia coli in comparison with its para analogue. The increased electron-deficiency of the metal center stabilizes Mn in its +2 oxidation state. The metal-centered Mn(III)/Mn(II) reduction potential, E((1/2))=+468 mV vs NHE, is increased by 416 mV with respect to non-brominated analogue, Mn(III)TM-3-PyP(5+) and is only 12 mV less positive than for para isomer. Yet, the complex is significantly more stable towards the loss of metal than its para analogue. As expected, based on the structure-activity relationships, an increase in E((1/2)) results in a higher catalytic rate constant for the O2*- dismutation, log k(cat)> or =8.85; 1.5-fold increase with respect to the para isomer. The IC(50) was calculated to be < or =3.7 nM. Manipulation of the electron-deficiency of a cationic porphyrin resulted, therefore, in the highest k(cat) ever reported for a metalloporphyrin, being essentially identical to the k(cat) of superoxide dismutases (log k(cat)=8.84-9.30). The positive kinetic salt effect points to the unexpected, unique and first time recorded behavior of Mn beta-octabrominated porphyrins when compared to other Mn porphyrins studied thus far. When species of opposing charges react, the increase in ionic strength invariably results in the decreased rate constant; with brominated porphyrins the opposite was found to be true. The effect is 3.5-fold greater with meta than with para isomer, which is discussed with respect to the closer proximity of the quaternary nitrogens of the meta isomer to the metal center than that of the para isomer. The potency of Mn(II)Br(8)TM-3-PyP(4+) was corroborated by in vivo studies, where 500 nM allows SOD-deficient E. coli to grow >60% of the growth of wild type; at concentrations > or =5 microM it exhibits toxicity. Our work shows that exceptionally high k(cat) for the O2*- disproportionation can be achieved not only with an N(5)-type coordination motif, as rationalized previously for aza crown ether (cyclic polyamines) complexes, but also with a N(4)-type motif as in the Mn porphyrin case; both motifs sharing "up-down-up-down" steric arrangement. 相似文献
5.
Dominique G. Gagnon 《生物化学与生物物理学报:生物膜》2005,1712(2):173-184
The accessibility of the hydrophilic loop between putative transmembrane segments XIII and XIV of the Na+/glucose cotransporter (SGLT1) was studied in Xenopus oocytes, using the substituted cysteine accessibility method (SCAM) and fluorescent labelling. Fifteen cysteine mutants between positions 565 and 664 yielded cotransport currents of similar amplitude than the wild-type SGLT1 (wtSGLT1). Extracellular, membrane-impermeant MTSES(−) and MTSET(+) had no effect on either cotransport or Na+ leak currents of wtSGLT1 but 9 mutants were affected by MTSES and/or MTSET. We also performed fluorescent labelling on SGLT1 mutants, using tetramethylrhodamine-5-maleimide and showed that positions 586, 588 and 624 were accessible. As amino acids 604 to 610 in SGLT1 have been proposed to form part of a phlorizin (Pz) binding site, we measured the KiPz and KmαMG for wtSGLT1 and for cysteine mutants at positions 588, 605-608 and 625. Although mutants A605C, Y606C and D607C had slightly higher KiPz values than wtSGLT1 with minimal changes in KmαMG, the effects were modest and do not support the original hypothesis. We conclude that the large, hydrophilic loop near the carboxyl terminus of SGLT1 is thus accessible to the external solution but does not appear to play a major part in the binding of phlorizin. 相似文献
6.
7.
The present study evaluated the effect of 5-hydroxytryptamine (5-HT) on intestinal Na(+)/H(+) exchanger (NHE) activity and the cellular signaling pathways involved in T84 cells. T84 cells express endogenous NHE1 and NHE2 proteins, detected by immunoblotting, but not NHE3. The rank order for inhibition of NHE activity in acid-loaded T84 cells was 5-(N-ethyl-N-isopropyl)-amiloride (EIPA; IC(50)=519 [465, 579] nM)>cariporide (IC(50)=630 [484, 819] nM)>amiloride (IC(50)=19 [16, 24] microM); the NHE3 inhibitor S3226 was found to be devoid of effect. This different inhibitory sensitivity indicates that both NHE1 and NHE2 isoforms may play an active role in Na(+)-dependent intracellular pH (pH(i)) recovery in T84 cells. Short-term exposure (0.5 h) of T84 cells to 5-HT increased NHE activity in a concentration-dependent manner. The stimulation induced by 5-HT (30 microM) was partially inhibited by both WAY 100135 (300 nM) and ketanserin (300 nM), antagonists of 5-HT(1A) and 5-HT(2) receptors, respectively. NHE activity was significantly increased by 8-OH-DPAT and alpha-methyl-5-HT, agonists of, respectively, 5-HT(1A) and 5-HT(2) receptors. An incubation of T84 cells with anti-G(s) and anti-G(beta) antibodies complexed with lipofectin did not prevent the 5-HT-induced stimulation of NHE activity. Overnight treatment with anti-G(ialpha1,2) and anti-G(q/11) antibodies complexed with lipofectin blocked the stimulatory effect induced by 8-OH-DPAT and alpha-methyl-5-HT, respectively. It is concluded that in T84 cells 5-HT enhances intestinal NHE activity through stimulation of G(ialpha1,2)-coupled 5-HT(1A) and G(q/11)-coupled 5-HT(2) receptors. 相似文献
8.
A new process for the removal of NOx by a combined Fe(II)EDTA absorption and microbial reduction has been demonstrated, in which part of the Fe(II)EDTA will be oxidized by oxygen in the flue gas to form Fe(III)EDTA. In former studies, strain FR-2 has been found to reduce Fe(III)EDTA efficiently. Otherwise, it has been reported that bio-electro reactor could efficiently provide a chance for simultaneous denitrification and metal ion removal. Therefore, a use of bio-electro reactor is suggested to promote the reduction of Fe(III)EDTA by strain FR-2 in this paper. The results showed that the concentration of Fe(III)EDTA decreased rapidly when electric current was applied, and that as the current density rose, the Fe(III)EDTA reduction rate increased while followed by a decrease afterward. The formation of the biofilm on the electrode was observed by ESEM (Environmental Scan Electro-Microscope). In addition, the Fe(III)EDTA reduction rate obviously decreased with the existence of NaNO2. 相似文献
9.
Megumi Hirono 《BBA》2007,1767(12):1401-1411
The H+-translocating inorganic pyrophosphatase is a proton pump that hydrolyzes inorganic pyrophosphate. It consists of a single polypeptide with 14-17 transmembrane domains (TMs). We focused on the third quarter region of Streptomyces coelicolor A3(2) H+-pyrophosphatase, which contains a long conserved cytoplasmic loop. We assayed 1520 mutants for pyrophosphate hydrolysis and proton translocation, and selected 34 single-residue substitution mutants with low substrate hydrolysis and proton-pump activities. We also generated 39 site-directed mutant enzymes and assayed their activity. The mutation of 5 residues in TM10 resulted in low energy-coupling efficiencies, and mutation of conserved residues Thr409, Val411, and Gly414 showed neither hydrolysis nor pumping activity. The mutation of six, five, and four residues in TM11, 12, and 13, respectively, gave a negative effect. Phe388, Thr389, and Val396 in cytoplasmic loop i were essential for efficient H+ translocation. Ala436 and Pro560 in the periplasmic loops were critical for coupling efficiency. These low-efficiency mutants showed dysfunction of the energy-conversion and/or proton-translocation activity. The energy efficiency was increased markedly by the mutation of two and six residues in TM9 and 12, respectively. These results suggest that TM10 is involved in enzyme function, and that TM12 regulate the energy-conversion efficiency. H+-pyrophosphatase might involve dynamic linkage between the hydrophilic loops and TMs through the central half region of the enzyme. 相似文献
10.
Tatyana A. Rodina Andrey V. Gerasimenko Tatyana S. Philippova 《Inorganica chimica acta》2011,368(1):263-270
Crystalline bis(N,N-di-iso-butyldithiocarbamato-S,S′)(pyridine)cadmium(II) - adduct 1 was prepared and studied by means of multinuclear 13C, 15N, 113Cd CP/MAS NMR spectroscopy, single-crystal X-ray diffraction and simultaneous thermal analysis (STA). In molecular structure 1, the cadmium atom coordinates with four sulphur atoms and one nitrogen atom of pyridine, forming a coordination polyhedron [CdS4N], whose geometry is an almost ideal tetragonal pyramidal (C4v). The coordinated py molecule is in the apical position, while two structurally non-equivalent di-iso-butyldithiocarbamate ligands, playing the same terminal S,S′-chelating function, define the basal plane. To characterise additionally the structural state of the cadmium atom in this fivefold coordination, 113Cd chemical shift anisotropy (CSA) parameters, δaniso and η, were calculated from experimental MAS NMR spectra that revealed an almost axially symmetric 113Cd chemical shift tensor. From a combination of TG and DSC measurements taken under an argon atmosphere, we found that the mass of adduct 1 is lost in two steps involving initial desorption of coordinated py molecules with subsequent thermal destruction of liberated cadmium(II) di-iso-butyldithiocarbamate, with yellow-orange, fine-powdered solid CdS as the final product. 相似文献
11.
The reaction of 2-(2-aminophenyl)benzothiazole (Habt) with [Re(CO)5Br] led to the isolation of the rhenium(I) complex fac-[Re(Habt)(CO)3Br] (1). With trans-[ReOCl3(PPh3)2], the ligand Habt decomposed to form the oxofree rhenium(V) complex [Re(itp)2Cl(PPh3)] (2) (itp = 2-amidophenylthiolate). From the reaction of trans-[ReOBr3(PPh3)2] with 2-(2-hydroxyphenyl)benzothiazole (Hhpd) the complex [ReVOBr2(hpd)(PPh3)] (3) was obtained. Complexes 1-3 are stable and lipophilic. 1H NMR and infrared assignments, as well as the X-ray crystal structures, of the complexes are reported. 相似文献
12.
Cytochrome bd is a terminal quinol:O2 oxidoreductase of respiratory chains of many bacteria. It contains three hemes, b558, b595, and d. The role of heme b595 remains obscure. A CO photolysis/recombination study of the membranes of Escherichia coli containing either wild type cytochrome bd or inactive E445A mutant was performed using nanosecond absorption spectroscopy. We compared photoinduced changes of heme d-CO complex in one-electron-reduced, two-electron-reduced, and fully reduced states of cytochromes bd. The line shape of spectra of photodissociation of one-electron-reduced and two-electron-reduced enzymes is strikingly different from that of the fully reduced enzyme. The difference demonstrates that in the fully reduced enzyme photolysis of CO from heme d perturbs ferrous heme b595 causing loss of an absorption band centered at 435 nm, thus supporting interactions between heme b595 and heme d in the di-heme oxygen-reducing site, in agreement with previous works. Photolyzed CO recombines with the fully reduced enzyme monoexponentially with τ ∼ 12 μs, whereas recombination of CO with one-electron-reduced cytochrome bd shows three kinetic phases, with τ ∼ 14 ns, 14 μs, and 280 μs. The spectra of the absorption changes associated with these components are different in line shape. The 14 ns phase, absent in the fully reduced enzyme, reflects geminate recombination of CO with part of heme d. The 14-μs component reflects bimolecular recombination of CO with heme d and electron backflow from heme d to hemes b in ∼ 4% of the enzyme population. The final, 280-μs component, reflects return of the electron from hemes b to heme d and bimolecular recombination of CO in that population. The fact that even in the two-electron-reduced enzyme, a nanosecond geminate recombination is observed, suggests that namely the redox state of heme b595, and not that of heme b558, controls the pathway(s) by which CO migrates between heme d and the medium. 相似文献
13.
Trafficking of an acylated cytosolic protein: newly synthesized p56(lck) travels to the plasma membrane via the exocytic pathway
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The Src-related tyrosine kinase p56(lck) (Lck) is primarily expressed in T lymphocytes where it localizes to the cytosolic side of the plasma membrane and associates with the T cell coreceptors CD4 and CD8. As a model for acylated proteins, we studied how this localization of Lck is achieved. We followed newly synthesized Lck by pulse-chase analysis and found that membrane association of Lck starts soon after synthesis, but is not complete until at least 30-45 min later. Membrane-binding kinetics are similar in CD4/CD8-positive and CD4/CD8-negative cells. In CD4-positive T cells, the interaction with CD4 rapidly follows membrane association of Lck. Studying the route via which Lck travels from its site of synthesis to the plasma membrane, we found that: CD4 associates with Lck within 10 min of synthesis, long before CD4 has reached the plasma membrane; Lck associates with intracellular CD4 early after synthesis and with cell surface CD4 at later times; and transport of CD4-bound Lck to the plasma membrane is inhibited by Brefeldin A. These data indicate that the initial association of newly synthesized Lck with CD4, and therefore with membranes, occurs on intracellular membranes of the exocytic pathway. From this location Lck is transported to the plasma membrane. 相似文献
14.
A new zinc(II) compound, [Zn2(Hsal)4(4,4′-bpe)2] · [Zn(Hsal)2(4,4′-bpe)(DMF)(H2O)] · CH3OH (1) (Hsal = salicylate and 4,4′-bpe = trans-1,2-bis(4-pyridyl)ethylene) has been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The crystal structure consists of three independent moieties: [Zn2(Hsal)4(4,4′-bpe)2], [Zn(Hsal)2(4,4′-bpe)(DMF)(H2O)], and non-coordinated CH3OH molecule. In the compound two independent moieties which are connected by 4,4′-bpe to form 1-D chains, respectively, are further expended to accomplish 2-D network through hydrogen-bonding interactions between non-coordinated methanol and coordinated water molecule or carboxylate oxygen atoms of Hsal ligands. 相似文献
15.
Leigh A. Nelson Christine L. Lambkin Philip Batterham James F. Wallman Mark Dowton Michael F. Whiting David K. Yeates Stephen L. Cameron 《Gene》2012
Members of the Calliphoridae (blowflies) are significant for medical and veterinary management, due to the ability of some species to consume living flesh as larvae, and for forensic investigations due to the ability of others to develop in corpses. Due to the difficulty of accurately identifying larval blowflies to species there is a need for DNA-based diagnostics for this family, however the widely used DNA-barcoding marker, cox1, has been shown to fail for several groups within this family. Additionally, many phylogenetic relationships within the Calliphoridae are still unresolved, particularly deeper level relationships. Sequencing whole mt genomes has been demonstrated both as an effective method for identifying the most informative diagnostic markers and for resolving phylogenetic relationships. Twenty-seven complete, or nearly so, mt genomes were sequenced representing 13 species, seven genera and four calliphorid subfamilies and a member of the related family Tachinidae. PCR and sequencing primers developed for sequencing one calliphorid species could be reused to sequence related species within the same superfamily with success rates ranging from 61% to 100%, demonstrating the speed and efficiency with which an mt genome dataset can be assembled. Comparison of molecular divergences for each of the 13 protein-coding genes and 2 ribosomal RNA genes, at a range of taxonomic scales identified novel targets for developing as diagnostic markers which were 117–200% more variable than the markers which have been used previously in calliphorids. Phylogenetic analysis of whole mt genome sequences resulted in much stronger support for family and subfamily-level relationships. The Calliphoridae are polyphyletic, with the Polleninae more closely related to the Tachinidae, and the Sarcophagidae are the sister group of the remaining calliphorids. Within the Calliphoridae, there was strong support for the monophyly of the Chrysomyinae and Luciliinae and for the sister-grouping of Luciliinae with Calliphorinae. Relationships within Chrysomya were not well resolved. Whole mt genome data, supported the previously demonstrated paraphyly of Lucilia cuprina with respect to L. sericata and allowed us to conclude that it is due to hybrid introgression prior to the last common ancestor of modern sericata populations, rather than due to recent hybridisation, nuclear pseudogenes or incomplete lineage sorting. 相似文献
16.
M.S. Mary Mangaiyarkarasi S. Vincent S. Janarthanan T. Subba Rao B.V.R. Tata 《Saudi Journal of Biological Sciences》2011,18(2):157-167
Detoxification of Cr(VI) under alkaline pH requires attention due to the alkaline nature of many effluents. An alkaliphilic gram-positive Bacillus subtilis isolated from tannery effluent contaminated soil was found to grow and reduce Cr(VI) up to 100% at an alkaline pH 9. Decrease in pH to acidic range with growth of the bacterium signified the role played by metabolites (organic acids) in chromium resistance and reduction mechanism. The XPS and FT-IR spectra confirmed the reduction of Cr(VI) by bacteria into +3 oxidation state. Chromate reductase assay indicated that the reduction was mediated by constitutive membrane bound enzymes. The kinetics of Cr(VI) reduction activity derived using the monod equation proved (Ks = 0.00032) high affinity of the organism to the metal. This study thus helped to localize the reduction activity at subcellular level in a chromium resistant alkaliphilic Bacillus sp. 相似文献
17.
Blad CC von Frijtag Drabbe Künzel JK de Vries H Mulder-Krieger T Bar-Yehuda S Fishman P Ijzerman AP 《Purinergic signalling》2011,7(4):453-462
We tested a panel of naturally occurring nucleosides for their affinity towards adenosine receptors. Both N
6-(2-isopentenyl)adenosine (IPA) and racemic zeatin riboside were shown to be selective human adenosine A3 receptor (hA3R) ligands with affinities in the high nanomolar range (K
i values of 159 and 649 nM, respectively). These values were comparable to the observed K
i value of adenosine on hA3R, which was 847 nM in the same radioligand binding assay. IPA also bound with micromolar affinity to the rat A3R. In a functional assay in Chinese hamster ovary cells transfected with hA3R, IPA and zeatin riboside inhibited forskolin-induced cAMP formation at micromolar potencies. The effect of IPA could be
blocked by the A3R antagonist VUF5574. Both IPA and reference A3R agonist 2-chloro-N
6-(3-iodobenzyl)adenosine-5′-N-methylcarboxamide (Cl-IB-MECA) have known antitumor effects. We demonstrated strong and highly similar antiproliferative
effects of IPA and Cl-IB-MECA on human and rat tumor cell lines LNCaP and N1S1. Importantly, the antiproliferative effect
of low concentrations of IPA on LNCaP cells could be fully blocked by the selective A3R antagonist MRS1523. At higher concentrations, IPA appeared to inhibit cell growth by an A3R-independent mechanism, as was previously reported for other A3R agonists. We used HPLC to investigate the presence of endogenous IPA in rat muscle tissue, but we could not detect the compound.
In conclusion, the antiproliferative effects of the naturally occurring nucleoside IPA are at least in part mediated by the
A3R. 相似文献
18.
C.V. Chandrasekaran H.B. DeepakP. Thiyagarajan S. KathiresanGopal Krishna Sangli M. DeepakAmit Agarwal 《Phytomedicine》2011,18(4):278-284
Glycyrrhiza glabra and its phytoconstituents have been known to possess widespread pharmacological properties as an anti-inflammatory, anti-viral, antitumour and hepatoprotective drug. In this study, we examined the inhibitory potential of extract of G. glabra (GutGard™) root and its phytoconstituents (glabridin, glycyrrhizin, and isoliquiritigenin) on both cyclooxygenase (COX) and lipoxygenase (LOX) products in order to understand the mechanism of its anti-inflammatory action. Inhibitory effect of GutGard™ and its phytoconstituents on lipopolysaccharide (LPS) induced prostaglandin E2 (PGE2), calcimycin (A23187) induced thromboxane (TXB2), and leukotriene (LTB4) release was studied using murine macrophages (J774A.1) and human neutrophil (HL-60) cells. Results revealed that, G. glabra and glabridin significantly inhibited PGE2, TXB2 (COX) and LTB4 (LOX), while, isoliquiritigenin exerted inhibitory effect only against COX products but failed to suppress LOX product. However, glycyrrhizin at the tested concentrations failed to exhibit inhibitory effect on both COX and LOX products. Here, we report for the first time that G. glabra (almost devoid of glycyrrhizin) exhibits anti-inflammatory property likely through the inhibition of PGE2, TXB2 and LTB4 in mammalian cell assay system, which could be influenced in part by glabridin and isoliquiritigenin. 相似文献
19.
Two new zinc(II)-triazole-aliphatic dicarboxylate coordination polymers, [Zn(trz)(Hsuc)]n (1), [Zn2(trz)2(tar)]n (2), have been hydrothermally synthesized by reaction of Zn salt, Htrz with H2suc and H2tar, respectively (Htrz = 1,2,4-triazole, H2suc = succinic acid, H2tar = tartaric acid).Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by X-ray powder diffraction, elemental analyses, IR spectra and TG analyses. Compound 1 displays a 2D layer structure containing {[Zn4(trz)4]4+}n layers decorated by the suc ligand. Compound 2 is in a 3D structure formed by the interconnection of 2D {[Zn4(trz)4]4+}n layers with tar ligand, resulting a 3,4-connected topological network. Due to the different coordination mode and conformation of aliphatic carboxylate ligand, the similar 2D {[Zn4(trz)4]4+}n layers stack in the -AAA- fashion in 1, while the {[Zn4(trz)4]4+}n layers hold together in the -ABAB- stacking sequence in 2. Additionally, the two compounds show strong fluorescence in the solid state at room temperature. 相似文献
20.
Although AHCYL2 (long-IRBIT) is highly homologous to IRBIT, which regulates ion-transporting proteins including the electrogenic Na+-HCO3− cotransporter NBCe1-B, its functions are poorly understood. Here, we found that AHCYL2 interacts with NBCe1-B in bovine parotid acinar cells using yeast two-hybrid, immunofluorescence confocal microscopy and co-immunoprecipitation analyses. Whole-cell patch-clamp experiments revealed that co-expression of AHCYL2 reduces the apparent affinity for intracellular Mg2+ in inhibition of NBCe1-B currents specifically in a HCO3−-deficient cellular condition. Our data unveil AHCYL2 as a potential regulator of NBCe1-B in mammalian cells. We propose that cytosolic ionic condition appropriate for AHCYL2 to function might be different from IRBIT. 相似文献